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use status symbols for inbound/outbound determination 

git-svn-id: http://op25.osmocom.org/svn/trunk@78 65a5c917-d112-43f1-993d-58c26a4786be
This commit is contained in:
mossmann 2008-06-04 16:05:54 +00:00
parent 42a7a96351
commit bc0256446b
1 changed files with 15 additions and 6 deletions
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21
wireshark/plugins/p25/packet-p25cai.c
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@ -38,7 +38,7 @@ void dissect_voice(tvbuff_t *tvb, proto_tree *tree, int offset);
void dissect_lsd(tvbuff_t *tvb, proto_tree *tree, int offset);
void dissect_lc(tvbuff_t *tvb, proto_tree *tree);
void dissect_es(tvbuff_t *tvb, proto_tree *tree);
tvbuff_t* extract_status_symbols(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
tvbuff_t* extract_status_symbols(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int *outbound);
tvbuff_t* build_hdu_tvb(tvbuff_t *tvb, packet_info *pinfo, int offset);
tvbuff_t* build_tsdu_tvb(tvbuff_t *tvb, packet_info *pinfo, int offset);
tvbuff_t* build_term_lc_tvb(tvbuff_t *tvb, packet_info *pinfo, int offset);
@ -392,7 +392,7 @@ dissect_p25cai(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
/* Set up structures needed to add the protocol subtree and manage it */
proto_item *ti, *nid_item, *du_item;
proto_tree *p25cai_tree, *nid_tree, *du_tree;
int offset;
int offset, outbound;
tvbuff_t *extracted_tvb, *du_tvb;
guint8 duid, last_block, mfid;
@ -444,7 +444,7 @@ dissect_p25cai(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
offset += 6;
/* Extract Status Symbols */
extracted_tvb = extract_status_symbols(tvb, pinfo, p25cai_tree);
extracted_tvb = extract_status_symbols(tvb, pinfo, p25cai_tree, &outbound);
/* process extracted_tvb from here on */
@ -503,9 +503,10 @@ dissect_p25cai(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
proto_tree_add_item(du_tree, hf_p25cai_ptbf, du_tvb, offset, 1, FALSE);
if (mfid > 1) {
proto_tree_add_item(du_tree, hf_p25cai_unknown_opcode, du_tvb, offset, 1, FALSE);
} else {
/* FIXME: how to know it is OSP vs. ISP? */
} else if (outbound) {
proto_tree_add_item(du_tree, hf_p25cai_osp_opcode, du_tvb, offset, 1, FALSE);
} else {
proto_tree_add_item(du_tree, hf_p25cai_isp_opcode, du_tvb, offset, 1, FALSE);
}
offset += 1;
proto_tree_add_item(du_tree, hf_p25cai_mfid, du_tvb, offset, 1, FALSE);
@ -625,7 +626,7 @@ dissect_es(tvbuff_t *tvb, proto_tree *tree)
/* Extract status symbols, display them, and return frame without status symbols */
tvbuff_t*
extract_status_symbols(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
extract_status_symbols(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int *outbound)
{
proto_item *ss_parent_item;
proto_tree *ss_tree;
@ -648,6 +649,14 @@ extract_status_symbols(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
if (i % 36 == 35) {
/* After every 35 dibits is a status symbol. */
proto_tree_add_item(ss_tree, hf_p25cai_ss, tvb, i/4, 1, FALSE);
/* Check to see if the status symbol is odd. */
if (tvb_get_guint8(tvb, i/4) & 0x1) {
/* Flag as outbound (only outbound frames should have odd status symbols).
* This may not be a very reliable means of determining the direction, but
* I haven't found anything better.
*/
*outbound &= 1;
}
} else {
/* Extract frame bits from between status symbols. */
/* I'm sure there is a more efficient way to do this. */